1. Field of the Invention
The present invention relates to a computer pointing device, and more particularly, to a computer mouse for scrolling a view of an image displayed over a computer monitor.
2. Description of the Prior Art
Window-based application interface has been commonly accepted by most computer users in today's computer world. When a window-based application displays an image over a computer monitor by using a window program, if the image is too big and can not be fit into a window which is displayed over the monitor by the window program, only a portion of the image will be displayed over the window and the window program will generate one or two scrolling bars over its right side or bottom side of the window for scrolling of the image within the window. The portion of the image displayed over the window is called a view and the scrolling bars are used to scroll the view of the image so that various portions of the image can be seen through the window.
U.S. Pat. No. 5,530,455, invented by Gillick et al, disclosed a computer mouse having a roller for scrolling the view of image over a computer monitor. The up and down scrolling of the view is controlled by rolling the roller forward or backward, and the lateral scrolling of the view is controlled by using both the roller and a shift key. The speed and amount of the scrolling of the view is in proportion to the speed and amount of roller's rotation. Several drawbacks have been discovered in using the roller of the mouse to control the view scrolling. First, frequent rolling of the roller may easily cause a soar finger if a task requires frequent rolling of the view. Second, when two dimensional view scrolling is required, a user has to constantly change the scrolling direction of the view which is quite inconvenient to a user. Third, both the up and down scrolling and the lateral scrolling are controlled by rolling the roller in forward and backward directions. If constant change is needed between the up and down scrolling and the lateral scrolling, a user has to constantly adapt himself for different control modes because the same forward or backward rolling of the roller will generate different scrolling action of the view which is quite difficult to a user.